1. Field of the Invention
This invention relates to a process cartridge, a developer cartridge and an electrophotographic image forming apparatus to which the process cartridge or/and the developer cartridge are detachably mountable.
Here, the electrophotographic image forming apparatus includes, for example, an electrophotographic copying machine, an electrophotographic printer (such as an LED printer or a laser beam printer), an electrophotographic facsimile apparatus and an electrophotographic word processor.
Also, as the process cartridge, charging means, developing means or cleaning means and an electrophotographic photosensitive member are integrally made into a cartridge detachably mountable to the main body of the image forming apparatus. Or at least one of charging means, developing means and cleaning means and an electrophotographic photosensitive member are integrally made into a cartridge detachably mountable to the main body of the image forming apparatus. Further, at least developing means and an electrophotographic photosensitive member are integrally made into a cartridge detachably mountable to the main body of the image forming apparatus.
2. Related Background Art
An image forming apparatus using the electrophotographic image forming process has heretofore adopted a process-cartridge system in which an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally made into a cartridge detachably mountable to the main body of the image forming apparatus. According to this process-cartridge system, the maintenance of the apparatus can be done by a user himself without resorting to a serviceman and therefore, operability can be improved markedly. So, this process cartridge system is widely used in image forming apparatuses.
As shown in FIG. 39 of the accompanying drawings, a process cartridge B is provided with large-diametered portions 21a as projected portions coaxially with the center axis of a photosensitive drum and outside the photosensitive drum, and the main body 17 of an image forming apparatus is provided with a guide portion 32 for guiding the projected portions 21a to a final set position. The process cartridge B is adapted to be manually pushed into the final set position along, the guide portion 32 provided on the main body 17 of the image forming apparatus by an operator or a serviceman.
In order to prevent image formation from being effected with the mounting remaining incomplete at that time, a projection 50 or the like is provided on the process cartridge B, and a detecting portion 51 for the projection 50 or the like is provided on the main body 17 of the image forming apparatus. When the process cartridge B has come to the vicinity of the final set position in the main body 17 of the image forming, apparatus, the detecting portion of the main body 17 of the image forming apparatus detects the projection or the like of the process cartridge B. When the process cartridge B is not detected, the main body 17 of the image forming apparatus judges that the process cartridge is absent, and does not carry out the image forming step. Also, the message that the process cartridge is absent is sent to the main body 17 of the image forming apparatus or a computer, and the warning that the process cartridge is absent is output.
The above-described conventional art is effective to detect whether the process cartridge is mounted on the main body of the image forming apparatus.